1. Field of the Invention
This invention relates to slide fasteners and in particular to slide fasteners having interlocked elements formed from filaments.
2. Description of the Prior Art
The prior art, as exemplified in U.S. Pat. No. 3,027,618 and No. 3,692,068 and Great Britain Pat. No. 981,511, contains slide fasteners having coupling elements formed from continuous filamentary material wherein portions of successive longitudinal sections of the filamentary material have been plastically deformed in cross section to form head portions, leg portions and connector portions joining the sections. The above U.S. Pat. No. 3,692,068 particularly discloses a method of and a loom for producing a tape having a list which may be hollow or in the form of a tube.
The plastically deformed portions in prior art filamentary coupling elements are not only deformed cross-sectionally but are also extended longitudinally due to the deformation; such longitudinal extension varies due to varying thicknesses of the filament to produce undesirable variation in the operational characteristics of the slide fasteners.
U.S. Pat. No. 3,018,610 discloses a filamentary material formed by combining a plurality of strands into a multistrand cord.